Methanation over transition-metal catalysts

Journal Article · Thu Apr 01 04:00:00 EST 1982 · J. Catal.; (United States)

OSTI ID:5296497

Agrawal, P K; Katzer, J R; Manogue, W H

Hydrogenation of CO over Ru films supported on Al/sub 2/O/sub 3/ was investigated in a gradientless, all-quartz, internal-recycle reactor at temperatures between 523 and 673/sup 0/K, at CO concentrations from 0.1 to 4%, and at H/sub 2/S concentrations bewteen 0 and 100 ppB in H/sub 2/ at atmospheric pressure. Methane is the major reaction product. The measured activation energy of 27 +- 1 kcal/mole is in good agreement with the values reported for highly dispersed Ru catalysts. Methanation is strongly inhibited by CO in the gas phase at temperatures between 523 and 673/sup 0/K. AES studies of aged catalysts show that there is no carbon preent either on the surface or in the subsurface regions. In the presence of 13 ppB H/sub 2/S in the gas phase the methanation activity is reduced by more than 10/sup 3/-fold at 663/sup 0/K. The activation energy remains 27 kcal/mole indicating that poisoning of Ru by H/sub 2/S is primarily a geometric effect. AES studies show the formation of a saturated two-dimensional surface sulfide, corresponding to each sulfur atom blocking two surface Ru atoms. There is no subsurface sulfur. This poisoning by sulfur is in marked contrast with the tolerance of Ru to poisoning by SO/sub 2/ during NO reduction by NH/sub 3/, and suggests that the nature of the reaction environment (strongly reducing vs mildly reducing) may have a significant effect on the tolerance of a catalyst to poisoning by sulfur. 11 figures.

• Research Organization: Univ. of Delaware, Newark
• OSTI ID: 5296497
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 74:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

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ACTIVATION ENERGY
ALKANES
AUGER ELECTRON SPECTROSCOPY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHROMATOGRAPHY
DATA
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
EXPERIMENTAL DATA
GAS CHROMATOGRAPHY
HIGH TEMPERATURE
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
INFORMATION
METALS
METHANE
MINERALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
POISONING
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
RUTHENIUM
SEPARATION PROCESSES
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SPECTROSCOPY
SULFIDES
SULFUR COMPOUNDS
SYNTHESIS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSITION ELEMENTS
YIELDS